[time-nuts] HP5370B & HP5345B Front-End IC Redesign Effort

Bob Camp kb8tq at n1k.org
Sun Jan 24 14:15:45 UTC 2016


Hi

Back when these counters (5345, 5370, 5335) all were new, the inputs were
the weak link on all of them. There were known “don’t do that” things on the line
that would blow out each of them. Regardless of the level of care and yelling, inputs
blew on a fairly regular basis. Probably 10% of the counters went back
for repair over a 5 year period. It was always a “swap out the entire board” sort
of repair and never was under $1K. We regularly spent the price of a new counter
each year on repairs. If there had been an easy way to fix them,  (or even to just
pay $500 for the chip) we would have done it.

Bob

> On Jan 24, 2016, at 8:34 AM, Dale Cannon <dalecan1 at cfl.rr.com> wrote:
> 
> Funny,
> 
> A friend asked me if I could replicate the front end for a 5370A, a many
> years back. I related to him that replicating the input chip was not a
> trivial task. His 5370A had been used (by someone else) for direct testing
> of controlled-motion DC motors and the front end had obviously been
> overstressed by voltage spiking. At the time, I had considered replicating
> the front-end probe circuit of a K100D logic analyzer: FET diff. pair
> followed by an ECL 10216 line driver. Obviously most daughterboard or dead
> bug modification approaches have downsides; in the end I just couldn't cut
> up the HP front end and told him to search for a more qualified repair
> facility.
> 
> BAMA boat anchors has the K100D manual and probe schematic.
> 
> 		Dale Cannon  KS4FA
> 
> 
> -----Original Message-----
> From: time-nuts [mailto:time-nuts-bounces at febo.com] On Behalf Of Mathew
> Breton
> Sent: Friday, January 22, 2016 5:15 PM
> To: time-nuts at febo.com
> Subject: [time-nuts] HP5370B & HP5345B Front-End IC Redesign Effort
> 
> I was gifted an HP 5370B with the usual problem: front-end problems,
> probably due to overstress. It is currently up and running again with a set
> of 5345A series A3/A4 boards as I wasn't able to get a cheap pair of
> 5088-706x hybrid ICs.
> This sounds like a common problem. As a result, I'm designing an open-source
> drop-in (hopefully) replacement. My hat is off to the original IC designer,
> as it is not a trivial effort due to the wide input signal common-mode
> range, and very tight trigger timing requirements. Other items (like the
> E-ECL) output) are also adding a bit of extra effort.
> I'm hoping that someone(s) might be interested in working with me on it. I
> would like to have my assumptions and math checked before I start the
> detailed design phase, and perhaps contribute some better ideas.
> In addition, it would be really helpful if someone could run a few rise-time
> dispersion tests on an instrument with a working "B"-series A3/A4 PCB set
> (my unit obviously doesn't qualify).
> Regards,
> Mat Breton 		 	   		  
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
> -----
> No virus found in this message.
> Checked by AVG - www.avg.com
> Version: 2016.0.7294 / Virus Database: 4492/11420 - Release Date: 01/17/16
> 
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.




More information about the Time-nuts_lists.febo.com mailing list